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nonblocking_server_example.c
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1 /*
2 * nonblocking_server_example.c
3 *
4 * This code demonstrates two methods of monitoring both an lo_server
5 * and other I/O from a single thread.
6 *
7 * Copyright (C) 2004 Steve Harris, Uwe Koloska
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation; either version 2.1 of the
12 * License, or (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU Lesser General Public License for more details.
18 *
19 * $Id$
20 */
21
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <sys/time.h>
25 #include <sys/types.h>
26 #include <strings.h>
27 #include <unistd.h>
28
29 #include "lo/lo.h"
30
31 int done = 0;
32
33 void error(int num, const char *m, const char *path);
34
35 int generic_handler(const char *path, const char *types, lo_arg **argv,
36 int argc, void *data, void *user_data);
37
38 int foo_handler(const char *path, const char *types, lo_arg **argv, int argc,
39 void *data, void *user_data);
40
41 int quit_handler(const char *path, const char *types, lo_arg **argv, int argc,
42 void *data, void *user_data);
43
44 void read_stdin(void);
45
46 int main()
47 {
48 int lo_fd;
49 fd_set rfds;
50 struct timeval tv;
51 int retval;
52
53 /* start a new server on port 7770 */
54 lo_server s = lo_server_new("7770", error);
55
56 /* add method that will match any path and args */
57 lo_server_add_method(s, NULL, NULL, generic_handler, NULL);
58
59 /* add method that will match the path /foo/bar, with two numbers, coerced
60 * to float and int */
61 lo_server_add_method(s, "/foo/bar", "fi", foo_handler, NULL);
62
63 /* add method that will match the path /quit with no args */
64 lo_server_add_method(s, "/quit", "", quit_handler, NULL);
65
66 /* get the file descriptor of the server socket, if supported */
67 lo_fd = lo_server_get_socket_fd(s);
68
69 if (lo_fd > 0) {
70
71 /* select() on lo_server fd is supported, so we'll use select()
72 * to watch both stdin and the lo_server fd. */
73
74 do {
75
76 FD_ZERO(&rfds);
77 #ifndef WIN32
78 FD_SET(0, &rfds); /* stdin */
79 #endif
80 FD_SET(lo_fd, &rfds);
81
82 retval = select(lo_fd + 1, &rfds, NULL, NULL, NULL); /* no timeout */
83
84 if (retval == -1) {
85
86 printf("select() error\n");
87 exit(1);
88
89 } else if (retval > 0) {
90
91 if (FD_ISSET(0, &rfds)) {
92
93 read_stdin();
94
95 }
96 if (FD_ISSET(lo_fd, &rfds)) {
97
98 lo_server_recv_noblock(s, 0);
99
100 }
101 }
102
103 } while (!done);
104
105 } else {
106
107 /* lo_server protocol does not support select(), so we'll watch
108 * stdin while polling the lo_server. */
109 #ifdef WIN32
110 printf("non-blocking input from stdin not supported under Windows\n");
111 exit(1);
112 #else
113 do {
114
115 FD_ZERO(&rfds);
116 FD_SET(0, &rfds);
117 tv.tv_sec = 0;
118 tv.tv_usec = 10000;
119
120 retval = select(1, &rfds, NULL, NULL, &tv); /* timeout every 10ms */
121
122 if (retval == -1) {
123
124 printf("select() error\n");
125 exit(1);
126
127 } else if (retval > 0 && FD_ISSET(0, &rfds)) {
128
129 read_stdin();
130
131 }
132
133 lo_server_recv_noblock(s, 0);
134
135 } while (!done);
136 #endif
137 }
138
139 return 0;
140 }
141
142 void error(int num, const char *msg, const char *path)
143 {
144 printf("liblo server error %d in path %s: %s\n", num, path, msg);
145 }
146
147 /* catch any incoming messages and display them. returning 1 means that the
148 * message has not been fully handled and the server should try other methods */
149 int generic_handler(const char *path, const char *types, lo_arg **argv,
150 int argc, void *data, void *user_data)
151 {
152 int i;
153
154 printf("path: <%s>\n", path);
155 for (i=0; i<argc; i++) {
156 printf("arg %d '%c' ", i, types[i]);
157 lo_arg_pp(types[i], argv[i]);
158 printf("\n");
159 }
160 printf("\n");
161 fflush(stdout);
162
163 return 1;
164 }
165
166 int foo_handler(const char *path, const char *types, lo_arg **argv, int argc,
167 void *data, void *user_data)
168 {
169 /* example showing pulling the argument values out of the argv array */
170 printf("%s <- f:%f, i:%d\n\n", path, argv[0]->f, argv[1]->i);
171 fflush(stdout);
172
173 return 0;
174 }
175
176 int quit_handler(const char *path, const char *types, lo_arg **argv, int argc,
177 void *data, void *user_data)
178 {
179 done = 1;
180 printf("quiting\n\n");
181
182 return 0;
183 }
184
185 void read_stdin(void)
186 {
187 char buf[256];
188 int len = read(0, buf, 256);
189 if (len > 0) {
190 printf("stdin: ");
191 fwrite(buf, len, 1, stdout);
192 printf("\n");
193 fflush(stdout);
194 }
195 }
196
197 /* vi:set ts=8 sts=4 sw=4: */